Be a mulching maniac.

Mulch acts as a suffocating blanket by preventing light from reaching weed seeds. At the same time, it holds moisture for your plants and provides nutrients for your soil as it decomposes. Apply coarse mulch, such as bark or wood chips, directly onto soil. Leaves, grass clippings, or straw work better as a weed deterrent with a separating layer of newspaper, cardboard, or fabric between them and the soil.